Loss of coolant....

Guys,

Looking for some ideas on what to check on my 1998 Accord 4cyl 2.3L that is losing coolant. I have a hard time judging how much I'm losing, but I think I'm adding about 16 oz every 2-3 weeks, but you shouldn't use any coolant on a properly functioning sealed system with a submerged overflow tube. This has been going on for at least 3-4 months.

The engine is clean, and I don't see any evidence anywhere of a leak. There doesn't seem to be any coolant drips anywhere, and when I pull into the garage with a hot engine and pop the hood, I don't smell any coolant smell. I don't think it is an external leak, but the evidence seems to point to an external leak.

I am not "making" oil and the oil looks normal on the dipstick and no smell. I did see a very small trace of a brown "sludge" on the underside of the oil fill cap, but it is cold here and that isn't unusual in cold weather.

The coolant looks perfect - no brown color or anything, so I don't think I have a combustion leak. I haven't noticed any smoke out of the exhaust when cold (but it's hard to tell in cold weather), and I'd think that the cylinder pressure would put combustion gases in the coolant when operating versus coolant getting pushed into the cylinder.

Only other thing I can think of is a cracked throttle body because I seem to recall that the throttle body is heated on this engine, but I haven't checked yet.

Anyone have any ideas? If the coolant level wasn't dropping, I would have no evidence of a problem. I think I will replace the cap first off to make sure I'm not just losing coolant to evaporation, but I don't think that is the problem......

Thanks,
Glen

Check your radiator tanks, they are plastic and when the seal goes bad they will leak out under pressure. It can be hard to find if it is down low.
Jeff

Check your radiator tanks, they are plastic and when the seal goes bad they will leak out under pressure. It can be hard to find if it is down low.
Jeff

Beat me to it...

Just about all the Accords I dealt with in the shop that had mystery leaks were coming either from the tank gaskets, like he said, or if they've ever been thumped even lightly in the front end, the tanks will get hairline cracks around their mounts at the core support.

They can be really frustrating to find, you have to fill the radiator to the top and pressure test to see the leak, unless it's been going on long enough to have formed the tell-tale crusty white stain of coolant leakage with evaporation.

Hmm....very interesting. I did have a small accident on the front about 2 years ago that barely scuffed the bumper and just bent the front 1/2" of the hood. That may have been enough, however, and it may be getting worse now and I've begun to notice it.

I'm surprised I've not been able to see the evidence of the crack (I've looked very closely to the underside of the car from below), but the scenario you both mention seems plausible, especially since I might be losing just a tiny bit each drive cycle. I've got a pit in my garage, so I'll inspect it a lot closer this weekend. I'm assuming that these new Valeo plastic radiators are not generally fixable and are just a replacement item (?).

Thanks for the tips! Glen

A radiator shop can put new tanks and gaskets on, but I'd probably go for a new one, if the price isn't that much difference.

FYI....I think the problem is minor. I was looking under the car, and noticed wetness on the frame below where the passenger's feet would be. Apparently I didn't the upper heater core hose installed quite right when I had done some work awhile back. I had pressed it all the way up against the firewall, and against the firewall grommet. The hose must have been leaking, and the coolant was leaking into the car and also between what must be a twin wall firewall. It didn't leak on the engine compartment side because the hose was pressed up against the grommet.

Once I pulled the carpet up I found all the coolant I lost....weird thing is that I never smelled any coolant, and never found drips on the ground.

I made sure the hose was installed correctly and am drying out the carpet padding now. I had pulled out the seat as well to expose the padding. I'll drive it a few days with the carpet peeled back to make sure it fixed it. If the cooler core is bad, I should know soon. I think the core is okay because the upper tube is the one tha twas wet, not the lower one.....


Thanks for the tips....Glen

Once I pulled the carpet up I found all the coolant I lost....weird thing is that I never smelled any coolant, and never found drips on the ground.

I made sure the hose was installed correctly and am drying out the carpet padding now. I had pulled out the seat as well to expose the padding. I'll drive it a few days with the carpet peeled back to make sure it fixed it. If the cooler core is bad, I should know soon. I think the core is okay because the upper tube is the one tha twas wet, not the lower one.....


Thanks for the tips....Glen

You need to check that the A/C core drain on the engine compartment side isn't blocked, it sounds like it is, because leakage from the core will usually run outta there, if it gets on the carpet, the box around the heat/evap cores is full. That's if yours reside in the same box like mine...I can't remember on Accords.